Objective To study the cl inical characteristics of sacrum echinococcosis disease so as to provide a basis for its diagnosis and treatment. Methods Between July 1999 and August 2010, 14 cases of sacrum echinococcosis disease were treated and the cl inical data were analysed retrospectively. There were 6 males and 8 females with an average age of 28.7 years (range, 16-58 years). The median disease duration was 5.7 years (range, 6 months to 11 years). Twelve cases came from cattle area or had a history of close contact with dogs and sheep; 12 patients had a history of lung or l iver hydatid disease. The main clinical symptoms were lumbosacral and lower extremity pain, one or both lower extremities and perineal hypoesthesia, the gradual dysfunction of both lower extremities and neurogenic bladder and bowel, and decreased force of urination. The imaging examination showed multicystic bone erosion. The Casoni test was performed in 10 cases and the results were positive in 8 cases. The eight immunoserology markers of hydatidosis were detected in 4 cases, and the results were all positive. After entire debridement of the focus, defects were repaired with autogenous bone, allogeneic bone, artificial bone, or bone cement, and then albendazole was used as a routine treatment for 3 months. Results Incisions healed by first intention, and no compl ication occurred. All patients were followed up 6 months to 11 years with a median time of 5.7 years. The preoperative cl inical symptoms were rel ieved. Eight cases recurred at 6 months to 3 years after operation; after debridement (3 times in 5 and 5 times in 1) and the lesions marginal resection with a high-speed burr (2 cases), the symptoms were relieved in different degrees without recurrence. No hydatid disease occurred and spreaded. Conclusion The cl inical manifestation of sacrum is not typical, which is easy to be misdiagnosed. MRI is helpful to diagnosis sacrum echinococcosis disease; serological examination is the major method of identification diagnosis, and surgery is the main treatment method.
Objective To evaluate the effects of sacrectomy extent on the stabil ity of lumbo-il iac fixation using single or dual il iac screw technique, and to determine which conditions require the dual il iac screw technique. Methods Nine fresh L2 to pelvic specimens were harvested from donated adult cadavers. After testing the intact state simulated by L3-5 pedicle screw fixation, sequential partial sacrectomies and L3 to il iac fixation using bilateral single il iac screw (Single) wereconducted on the same specimen as follows: in group A, under S1 partial sacrectomy and Single; in group B, under 1/2 S1 partial sacrectomy and Single; in group C, one-side (left) sacroil iac joint resection and Single; in group D, total sacrectomy and Single; and in group E, the single il iac screw was replaced by dual il iac screws based on group D. Biomechanical testing was performed on a material testing machine under 0-800 N compression and —7-7 N•m torsion loading modes for construct stiffness evaluation. Results The compressive stiffness of intact condition was (392 ± 119) N/mm, groups A, B, C, D, and E obtained 106.4% ± 9.5%, 102.7% ± 8.0%, 92.2% ± 10.1%, 72.7% ± 8.0%, and 107.7% ± 10.7% of intact condition, respectively. No significant differences were found among groups A, B, C, and the intact state (P gt; 0.05), however, the four groups showed significantly higher compressive stiffness than group D (P lt; 0.05). Although group E exhibited a comparable compressive stiffness with groups A, B, and intact state (P gt; 0.05), it displayed markedly higher compressive stiffness than groups C and D (P lt; 0.05). The torsional stiffness of intact state was (3.22 ± 1.23) N•m/deg. Groups A, B, C, D, and E acquired 105.4% ± 10.1%, 89.8% ± 12.3%, 75.9% ± 10.6%, 71.2% ± 10.2%, and 109.1% ± 16.9% of intact state, respectively. No significant differences were detected among groups A, B, E, and the intact state (P gt; 0.05). However, groups C and D showed remarkably lower torsional stiffness than groups A, E, and the intact state (P lt; 0.05). Importantly, group E offered remarkably higher torsional stiffness than group B (P lt; 0.05). Conclusion After under 1/2 S1 partial sacrectomy, single il iac screw technique could effectively restore local stabil ity; whereas it could hardly provide adequate stabil ity for further resection of one-side sacroil iac joint or total sacrectomy; in such situation, the use of dual il iac screw technique could obtain sufficient construct stabil ity. Therefore, in the surgical treatment of sacral tumor, the dual il iac screw technique should be considered for the unstable conditions of totalsacrectomy or under 1/2 S1 sacrectomy with one-side sacroil iac joint resection.
Objective To biomechanically compare the maximum pull-out strengths among two pedicle screws and three salvage techniques using poly methylmethacrylate (PMMA) augmentation in osteoporotic sacrum, and to determine which PMMA augmentation technique could serve as the salvage fixation for loosening sacral pedicle screws. Methods Eleven sacra were harvested from fresh adult donated cadavers, aged from 66 to 83 years (average 74.4 years) and included 5 men and 6 women. Radiography was used to exclude sacra that showed tumor or inflammatory or any other anatomic abnormal ities. Following the measurement of bone mineral density, five sacral screw fixations were sequentially establ ished on the same sacrum as follows: unicortical pedicle screw (group A), bicortical pedicle screw (group B), unicortical pedicle screw with the traditional PMMA augmentation (group C), ala screw with the traditional PMMA augmentation (group D), and ala screw with a kyphoplasty-assisted PMMA augmentation technique (group E). According to the sequence above, the axial pull-out test of each screw was conducted on a MTS-858 material testing machine. The maximum pull-out forces were measured and compared. The morphologies of PMMA augmented screws after being pulled-out were also inspected. Results The average bone mineral density of 11 osteoporotic specimens was (0.71 ± 0.08) g/cm2 . By observation of the pull-out screws, groups C, D, E showed perfect bonding with PMMA, and group E bonded more PMMA than groups C and D. The maximum pull-out forces of groups A, B, C, D, and E were (508 ± 128), (685 ± 126), (846 ± 230), (543 ± 121), and (702 ± 144) N, respectively. The maximum pull-out strength was significantly higher in groups B, C, and E than in groups A and D (P lt; 0.05), and in group C than in groups B and E (P lt; 0.05). There was no significant difference in pull-out strength between groups A and D, and between groups B and E (P gt; 0.05). Conclusion For sacral screw fixation of osteoporotic patients with bone mineral density more than 0.7 g/cm2, bicortical pedicle screw could acquire significantly higher fixation strength than the unicortical. Once the loosening of pedicle screw occurs, the traditional PMMA augmentation or ala screw with kyphoplasty-assisted PMMA augmentation may serve as a suitable salvage technique.
To evaluate the cl inical effect of pedical screw systems fixed between lumbar and il ium for treatment of sacral fractures. Methods From June 2003 to June 2009, 21 cases of sacral fracture (29 sides including monolateral 13 cases and bilateral 8 cases) were treated with pedical screw systems to have reduction and fixation. There were 12 males and 9 females, aging 23-59 years (38.2 years on average). Fractue was caused by traffic accident in 12 cases, by fall ingfrom height in 7 cases, and by crash in 2 cases. Screws were inserted into lumbar pedicles and il iac crests. Decompression was used in 4 cases compl icated by sacral nerves injury, and reductions and fixations were used in 12 cases compl icated anterior pelvic or acetabulum injury. The preoperative proximal displacement at the injured side of the pelvis was (16.29 ± 6.47) mm compared with contralateral pelvis. Results All incisions healed primarily with no compl ication of infection. Twentyone patients were followed up 6 months to 6 years. Cl inical heal ing time of fracture was 6-9 weeks. In 4 cases compl icated by S1 or S2,3 nerves injury, the function recovered completely after 4-9 weeks. In other 17 patients, no compl ication of intraoperative nerve injury occurred. All patients could walk and squat after 6-12 weeks of operation. No breakage or displacement of implant occurred. The postoperative proximal displacement at the injured side of the pelvis was (3.51 ± 0.68) mm compared with contralateral pelvis, showing significant difference (P lt; 0.01) when compared with preoperative one. Conclusion It is a novel choice to have reduction and internal fixation for sacral fracture with pedical screw systems fixed between lumbar and il ium. The strict regulation of indication and skill is the key to prevent compl ication.
Objective To study the therapeutic effect of combining vacuum seal ing drainage (VSD) with gluteus maximus myocutaneous flap on the repair of soft tissue defect caused by the resection of sacral tumors. Methods From June2007 to June 2008, 6 patients with skin and soft tissue necrosis in the sacrococcygeal region, deep infection, and formation of cavity at 3-6 weeks after sacral tumors resection were treated. There were 4 males and 2 females aged 17-51 years old. The size of skin and soft tissue defects ranged from 15 cm × 11 cm × 6 cm to 20 cm × 18 cm × 7 cm. Every patient underwent VSD treatment for 7-10 days, and the recombinant bovine bFGF was injected into the wound intermittently for 7-14 days (250-300 U/ cm2 once, twice daily). The wound was repaired by either the gluteus maximus myocutaneous flap (5 cases) or the lumbar-gluteus flap (1 case), and those flaps were 9 cm × 9 cm-20 cm × 18 cm in size. The donor site were sutured or repaired with spl itthickness skin graft. Results All the flaps survived uneventfully. The wound healed by first intention in 5 cases, but 1 case suffered from fat l iquefaction 2 weeks after operation and healed after drainage and dressing change. All the donor sites healed by first intention, and all the skin grafts survived uneventfully. All the patients were followed up for 6-10 months, there was no relapse of sacral tumor, and the flaps showed no obvious swell ing with good color and elasticity. Conclusion With fewer compl ications, the combination of VSD and gluteus maximus myocutaneous flap is a safe and rel iable operative method for repairing the skin and soft tissue defects caused by the resection of sacral tumors.
Objective To investigate the biomechanical differences of three internal fixation approaches, namely improved Galveston (IG), reconstruction plate (RP), and il iosacral screw (LS) to the posterior pelvic ring fracture dislocation and provide experimental evidence for the cl inical appl ication of proper internal fixation method. Methods Six donatedfresh adult cadaver pelvic specimens (age averaged 45 years old) were numbered randomly and their normal biomechanics were tested by the measure instrument (MTS855 Mini-Blonix). The displacement values of normal pelvis were measured under the vertical compression (800 N) and reverse direction compression (8 N·m). Then they were made into left Denis I pelvic fracture and fixed with the IG, RP, and LS, respectively, in different orders. Biomechanics test was conducted on the fixed pelvis from both the vertical and the reversed directions. Results Concerning the direction of vertical ity and torsion, the order of fracture displacement from small to large was the normal pelvis, LS, IG and RP. There was no significant difference between LS and the normal pelvis (P gt; 0.05), and the differences between other tow groups were significant (P lt; 0.05). Conclusion The LS fixation can provide better stabil ity for posterior pelvic ring fracture dislocation when compared with IG and RP.
Objective To study the MRI diagnosis of sacral fracture with sacral neurological damage and its cl inical appl ication. Methods From October 1999 to October 2007, 20 cases of sacral fracture (Denis classification, Type II)with sacral neurological damage were examined by obl ique coronal MRI of sacrum to show the whole length of sacral nerve. There were 17 males and 3 females, aged 30-55 years. The time from injury to hospital ization varied from 1 day to 23 months. The injury was caused by traffic accident in 10 cases, smash of heavy object in 8 cases and crush in 2 cases. Eight cases were accompanied by pubis fracture and 4 cases by urethral disruption. All patients accepted the examination of X-ray, CT and spiral CT 3D reconstruction. X-ray showed the displacement of fracture fragment was backwards and upwards, and sacral-hole l ine was vague, asymmetric and distorted. CT showed that sacral neural tube was left-right asymmetry, the displacement of fracture fragment was backwards and upwards, combining with the compression and intruding to sacrum center at different section levels. The cl inical manifestations, international standards for Neurological Classification of Spinal Cord Injury recommended by American Spinal Injury Association International Spinal Cord Society, comparison between normal and abnormal MRI and Gierada’s results were the basis for cl inical diagnose and MRI diagnose, which was confirmed by operation. Results Nerve injury diagnosed by cl inical manifestation were S1 (17 cases), S2 (14 cases), S3 (7 cases), and S4 (6 cases). Nerve injury diagnosedby MRI were S1 (17 cases), S2 (14 cases), S3 (3 cases), and S4 (2 cases). Nerve injury confirmed by operation were S1 (17 cases), S2 (14 cases), S3 (7 cases), and S4 (1 case). Obl ique coronal MRI of sacrum showed the whole length of sacral nerve and its adjacent relationship, detecting bone fragment compression and route alteration of never were evident in 5 cases, the fat disappearance around the site of nerve root injury in 19 cases, narrowness of sacral nerve canal in 17 cases and the abnormally enlarged sacral nerve in 11 cases. Conclusion Obl ique coronal MRI of sacrum is of great value in the local ization and the qual itative diagnosis of sacral neurological damage.